Chatly — Scalable Real-time Chat Backend

Chatly is a high-performance, scalable real-time chat backend built with Go. It features horizontal scaling via Redis Pub/Sub, production-grade security with JWT Refresh Token Rotation, and a robust Clean Architecture.

Chatly adalah backend chat real-time berperforma tinggi yang dibangun dengan Go. Fokus utama project ini adalah pada Scalability (Horizontal Scaling), Clean Architecture, dan Production-grade Security.

🛠️ Tech Stack

• Language: Go 1.25+
• HTTP Framework: Gin (High-performance web framework)
• Real-time: Gorilla WebSocket
• Persistence: PostgreSQL
• Cache & Pub/Sub (Scaling): Redis
• Authentication: JWT (v5) with Refresh Token Rotation & Reuse Detection
• Rate Limiter: Implementation of Sliding Window algorithm via Redis
• Deployment: Docker & Docker Compose (Multi-stage build)

📡 System Architecture

Sistem ini menggunakan Redis Pub/Sub untuk mensinkronisasi pesan antar instance server, memungkinkan Horizontal Scaling secara efisien.

graph TD
    UserA[User A] <--> |WebSocket| App1(App Instance 1)
    UserB[User B] <--> |WebSocket| App2(App Instance 2)
    
    App1 <--> |Pub/Sub| Redis{Redis Broker}
    App2 <--> |Pub/Sub| Redis
    
    App1 --> |Persist| DB[(PostgreSQL)]
    App2 --> |Persist| DB
    
    App1 -.-> |Rate Limit| Redis
    App2 -.-> |Rate Limit| Redis

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🚀 Fitur Utama

• WebSocket Scaling: Pesan tersinkronisasi antar banyak instance via Redis.
• Advanced Auth: Rotasi token otomatis untuk mencegah pembajakan sesi.
• Interactive Documentation: Swagger UI integrated for easy API testing.
• Demo Frontend: Simple HTML/JS client included for real-time demo.
• Unit Tested: Core logic covered with high-quality unit tests.
• Rate Limiting: Melindungi server dari spamming (20 req/menit per IP).
• Clean Architecture: Kode terstruktur rapi sehingga mudah di-maintain.
• Automatic Migrations: Skema database diperbarui otomatis saat startup dengan Advisory Lock.

🏗️ Struktur Proyek

• cmd/main.go: Entry point & Dependency Injection.
• internal/domain: Model data & Interface.
• internal/repository: Implementasi akses data (Postgres).
• internal/service: Logika bisnis & Unit Tests.
• internal/delivery: HTTP Handlers, Routing, & Swagger.
• static/: Frontend assets (HTML/CSS/JS).

⚙️ Cara Menjalankan

1. Prasyarat

• Docker & Docker Compose
• Pastikan Postgres dan Redis Anda yang sudah ada sedang berjalan.

2. Jalankan dengan Docker Compose

docker compose up --build

🧪 Panduan Testing

Testing via Swagger

1. Jalankan aplikasi: docker compose up
2. Buka http://localhost:8090/swagger/index.html
3. Anda bisa mencoba semua API (Register, Login, Me) langsung dari sana!

Testing via Frontend Demo

1. Buka http://localhost:8090/ di browser Anda.
2. Login menggunakan kredensial default (al@chatly.io / password123) atau register user baru.
3. Buka tab baru di browser ke http://localhost:8091/ (App 2).
4. Chat antar tab! Pesan akan sinkron secara real-time via Redis Pub/Sub.

Running Unit Tests

go test ./internal/service/... -v